In 2014, photographers Lora Scantling and Christy Goodger sent out an open call on Facebook that would change their lives forever.
Scantling's stepfather had been recently diagnosed with lung cancer, and she wanted to start a project that would pay tribute to him.
"I thought, 'Oh how sweet would it be and I put a post on Facebook asking if anyone knew of little kids battling cancer,'" she told ABC.
In the years since, Scantling has photographed dozens of pint sized cancer survivors for a project she calls "Little Heroes."
But three little girls stood out from the rest, in a photo that went viral around the world.
Three Little Angels
Three young girls from Oklahoma posed for the now-famous photo.
Six-year-old Rheann Franklin, center, was battling a rare brain tumor.
Five-year-old Ainsley Peters, on the right, was facing leukemia.
And Rylie Hughey, on the left, was only three, but living with kidney cancer.
All bald, dressed like angels and hugging each other close, the photo of the three girls resonated with people around the world and quickly went viral.
Ainsley's mother says the image is so moving because it's "a beautiful look at a horrifying struggle."
Scantling said it connected with so many because "you can feel what they're feeling."
The first noteworthy reunion of the three little models came less than a year after the original photo was taken.
This time, Ainsley and Rylie sported short hair, and posed for the photo in brightly colored dresses.
The photos marked a major milestone for all three girls: they were officially in remission.
You may notice that Rheann is still bald and has droopy eyes: while her hair will never grow back, these are just lasting signs of her victory over her brain tumor.
Scantling remembers that the girls were even in good spirits to match their bright outfits.
"It was just like a bunch of friends getting together," she remembered.
"They were bouncing off the walls, having fun, like, 'Oh my best friends are here.'"
But even though the three girls are now cancer survivors, Scantling wasn't ready to stop photographing them.
An Annual Tradition
The photographer says she plans to keep photographing Rheann, Ainsley and Rylie throughout their lives.
Sadly, in the years since the first photo was taken, her own stepfather has passed away.
But the three little girls continue to inspire people around the world.
"If I had to sum up Lora's photos in one word, it would be 'hope,'" said Rylie's mother.
"Strength comes in numbers, and I hope that another family in the middle of a battle with cancer can look at the photo and be inspired."
And to keep hope alive, Scantling plans to take as many photos of the trio as she can.
But for this year's photos, the girls were joined by someone new.
"Sometimes you never know how much time you have."
The new face in this year's photo of the girls is three-year-old Connor Lloyd.
Scantling is Lloyd's family photographer, and when she heard the young boy had been diagnosed with acute lymphoblastic leukemia, she invited him to pose with the girls.
"Sometimes you never know how much time you have," she explained to his mother.
Scantling says that "people have kind of forgotten what the original purpose of the picture was for" because the three girls are in remission.
"Connor will be in treatment for another three years, and yet he's always so happy and brave. Just like the girls, he's an inspiration."
The photographer says Connor is "responding well to treatment," so count on seeing him again when Scantling's next photo comes out.
"I'll keep taking this photo every year for as long as they want me to," she said.
"They're inspiring to all of us."
Best of luck to Rheann, Ainsley, Rylie and Connor!
For another inspiring cancer story, read about the baby born with both Down syndrome and cancer.
And here's another viral photo with a surprising update - remember those "hot cops" from a few years ago?